In a letter, NHS chief executive David Nicholson said: ‘If the proposed agreement is not accepted by union members, the government reserves the right to review its response to the NHS Pay Review Body recommendations and decide whether to accept, stage or abate them in the context of a one year settlement.'

Unite Head of Health Kevin Coyne said the letter was a clear threat to staff to ‘accept a below inflation three-year deal or face the consequences'.

He added that last year's 2.5 per cent staged award in England had created ‘an atmosphere of seething and simmering resentment.'

Unite has recommended that its members reject the pay offer, which would see nurses in the NHS receive a 2.75 per cent pay rise in 2008/9, a 2.4 per cent rise in 2009/10 and a 2.25 per cent rise in 2010/11.

The union said it was concerned about signing a three-year deal given the inflationary pressures in the economy.